Testing system



May 4.192e. 1,582,948

'J'. NL wALTERs Er AL l TESTING SYSTEM Patented May 4, 1926.

gUNITED STATES JAMES N. WALTERS, OF EAST ORANGE, NEW JERSEY, AND CLAUDE EWING, OF BROOK- LYN, NEW YORK, ASSIGNORS TO AMERICAN TELEPHONE AND TELEGRAPH COM- PANY, A CORPORATION OF NEW YORK.

TESTING SYSTEM.

Application mea August 1s, 1924. serial No. 732,846.

To @ZZ whom it may concern.'

Be it known that we, JAMES N. WALTERS and CLAUDE EWING, residing at East Orange and Brooklyn, in the counties of Essex and Kings'and States'of zNew Jersey and New York, respectively, have invented certain Improvements in Testing Systems, of which the following is a specification.

This invention relates to testing systems and more particularly to a testing' system for check testing selector and connector switches and their associated trunks in afull mechanical step-by-step machine switching system.

Heretofore, it has been customary to test the selector and 'connector switches and their associated trunk circuits byoperating th switching mechanism by hand.

The object of this invention is the speedy and thorough automatic testingof selector and connector switches and their associated trunk circuits. l

In accordance with this invention, a test set is equipped with a dial and suitable means for linking the test set to a selector switch. The dial is operated to set the switch on any desired trunk level, and the switch automaticallyr hunts for and connects with the first idle trunk, whereupon the apparatus in the test set functions and subjectsthe switch and the seized trunk to a series of tests. If the tests'progress properly indicating that the switch and trunk are in proper condition, an audible signal is received and the selector switch is caused to step ahead automatically to the next idle trunk in the group. If a defective circuit is encountered the switch stops and must be stepped ahead by the tester. After Vthe last trunk in a given level has either been tested or passed by, t-he switch releases and the tester proceeds to dial another digit corresponding to some other level in the switch. In the drawing comprising but a single sheet, the invent-ion is diagrammatically represented applied to a selector switch. The test set TS is shown at the left and a typical selector switch SS of the well known St-rowger type at the right. A circuit at S1 represents the first idle trunk in a group of trunks accessible to the selector switch.

It is believed that the invention will be fully understood froln the following detailed description of its operation during a typical test.

Testing trunks between, selectors. Dz'a1Zz'mg.-The clips TG1 and TG2 are respectively connected to the winding and the back contact 35 of the rotary magnet 41 as shown in the drawing, and the plug P is inserted in the test jack TJ of the selectorl switch SS. The key TK of the test set TS is operated, closing the impulse circuit to operate the relay 1 of the selector switch SS as follows: battery, right winding of relay 1, 2, 3, 4, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 15, 16, 17, 18, left windingof relay 1, 19, 20, 21 to ground.V Relay 1, operated, closes at its armature 103 an obvious circuit to operate relay 22. Relay 22, operated, connects ground by way of its armature 32 to the test terminal 61 of the selector switch SS, causing the switch to test busy to all selector switching having access thereto.

The dial'I) is now operatedand released in accordance with the digit corresponding to the particular level desired, and as the dial returns to normal, the impulse circuit previously traced is intermittently opened and closed at the impulse springs 9 and 10 of the dial l). When the impulse circuit is opened, relay 1 releases, and a lcircuit is closed to operate the vertical magnet 24 and relay 23 in series as follows; battery,

winding of the vertical magnet 24, winding of relay 23, 104, 103, 38 to ground. Relay 22 is made slow-to-release so that it will remain operated when its circuit is momentarily opened at 103 by the release of theV impulse relay 1. The vertical Lmagnet 24, operated, steps the selector rod 105one step in accordance with the primary movement of.

of the impulse springs 9' and 10 of the dial D, relay 1 reoperates momentarily, thus opening 'the circuit through the vertical magnet 24 and relay 23 in series, but relay 23, which is designed to be slow-to-release,'

remains operated until the circuit previously established through the vertical magnet 24 -and relay 23 is again closed by the release number of steps in accordance with theV primary movement'of the selector switch SS. At the end of the impulse train, relay 1 remains operated and relay 23 and the vertical magnet 24 release. i/Vhen relay 23 releases, a circuit is closed to operate the rotary'magnet 41 as follows: battery, winding of rotary magnet 41, 40, 39, 42, 29, 30, 31, 32 to ground. The rotary magnet 41, operated, initiates the secondary movement of the switch and opens at 34 and 35 the locking circuitV previously traced for relay 25, which releases. Relay 25, released, opens at 39 and 40 the operating circuit forthe rotary magnetl 41, which likewise releases.

VThe brushes 55, 56 and 52 are now resting upon the terminals associated with the first trunk in the selected level, which we will assume to be busy, in which case solid ground at the test terminal. will be connected to the brush 52.

Trunk /zmitz'a/l/Vith ground connected to the brush 52 by way of test the terminal of the busy trunlr, a circuit is closed to operate relay 25 as follows: battery, winding of relay 25, 26, 27, 47, 48, 49, 50, 51, 52 to ground. Relay 25, operated, again close' the circuit previously traced to operate the rotary magnet 4l, which causes the brushes 55, 56 and 52 to be stepped to the terminals associated with the next trunk in the group. The operation of the rotary magnet 41 liliewise opens at 34 and 35 the locking circuit for relay 25, which again releases. lf the selected trunk is busy, ground at its test terminal will close the circuit previously traced by way of the brush 52 to reoperate relay 25, which in turn will reoperate the rotary magnet in the manner previously described, and the brushes 55, 56 and 52 will be stepped to the terminals associated with the next succeeding trunl in the group, as previously described. rThis cycle of operations will continue until an idle trunk is found, which we will assume to be the trunk associated with the selector switch S1, shown in the drawing.

Trunk testing-lith the brushes 55, 56V

and 52 resting upon the terminals 57 58 and 43 of the selector switch S1, the following circuit is closed to operate relay 5'3: battery, Winding of relay 25, 26, 27, 47, 43, 49, winding of relay 53, 31, 32 to ground. Relay 25 will not operate over this circuit due to the high resistance of the winding of relay 53 in series with it. The operation of relay 53 extends the test set TS throughto the trunk circuit of the selector switch S1. The lrey TK of the test set TS is now released and the key K is operated. The operation of relay 53 opened the circuit through the windings of relay l, which released, and in turn opened the circuitthrough relay 22, which likewise releases,

V'opening at 32 the operating circuit for relay Relay 53, however, does not release as a holding circuit is established by the operation of the key K over the following circuiti battery, winding of relay 25, 26, 27, 47, 43, 49, winding of relay 53, 66, 65, 64, 63, winding of relay 62 to ground. Relayl 62 operates in series with relay 53 over the circuit previously traced, closing an obvious circuit to operate relay 63.n lV ith relay 63 operated, the ring conductors of the test set TS, selector switch SS and switch S1 are connected in series, and if they are continuous, ungrounded and free from foreign battery, a circuit will be closed as `follows to operate relay 65 of the test set rlS: battery, right winding ontv relay 46 of the switch S1, 66, 69, 53, 56, 60,2, 3, 4, 14,67, 66, winding cf relay 65, 64 to ground. Relay 46 Vwill not operate over this circuit due to the high resistance of the winding of relay 65 in series with it. Relay 65, operated, connects the tip conductors of the test set TS, selector switch SS and switch S1 in series, and if they are continuous and free from foreign battery and ground, a circuit will be closed to operate relay 70, traced for convenience as'follows: ground, left winding of relay le, 75, 74, 57, 55, l59, i7, 1c, i5, 7s, 7e, wind.- ing of relay 70, 71 to battery. Relay 46 now operates, closing an obvious circuit to operate relay 44. Relay 44, operated, Vconnects ground` by way of its armature 45 to the test terminal 43 of the selector switch S1. A holding' circuit is now established for relay 53 of the selector switch SS as follows: battery, winding of relay 25.. 26, 27, 47, 48, 49, winding ofrelay 53, 54, 51, 52, 43, 45 to ground. Grounding the test terminalv 43 results in the short circuitingl of the winding of relay 62 of the test set TS, which releases. Relay 62, released, opens the circuit of relav 63 and closes a circuit to operate relay 76 as follows: battery, winding of relay 76, 77, 78, 79 to ground. Relay 76 locks by way of 8O and, 79 independently of relay 7 0. Relay 63 is made slow-torelease to delay the release of relays 65 and 70 until afterrelay 76 is operated and locked. Relay 63 released opens the circuit through relay 65, which releases. Relay 65, released, opens at 71` the circuit through relay 70, which releases. The release of relays 63 and 65 opens at 64 be of the type disclosed in the patent to Sandalls, No. 1,551,524, issued Nov. 17, 1925) at the distant oiiice is so arranged that after it has been seized it will cause the direction of the current supplied to the test set TS by the connector to be reversed intermittently (usually at the rate of about GO reversals per minute).

After dialing is completed, the following bridge is closed across the tip and ring con'- ductors ot the trunk circuit: tip conductor 15 of the plug l), 5, 6, 7, S, 9, 10, transmitter T, 96, winding of the polarized relay 86, 97, 13, 14 to the ring conductor l orn the plug' l. The relay S6 being polarized will not operate until, by the operation of the test line at the distant otlice, the direction of the current furnished to the test set TS, and consequently to the polarized relay 86, is reversed in a manner shown in the Sandalls application cited. When the polarized relay 8G operates on the reversed Current, a circuit is closed to operate relay 87, thereby closing at 90 an obvious circuit to liOht the lamp 89. lVhcn the direction ot' the current supplied to the test set TS is .again reversed, the polarized relay 86 releases, thus permitting the relay S8 to operate in series with the winding ot relay 8T. Relay 8S operated locks under control ot the key TK, and opens at 91 the circuit through the lamp S9, which is extinguished. I'lhe test line at the distant oilice continues to cause current to be supplied to the test set, lirst in one direction and then in the opposite direction, and the polarized relay 86 continues to operate and release in unison therewith, thus flashing the lamp S9 until the tester releases the circuit by restoring the key TK to normal.

The test set is also equipped with a transmitter T so that the tester may converse over the circuit established it he so desires.

vWhat is claimed is:

1. il test set tor testinga switching device and the groups of circuits accessible thereto comprising, means tor operating the switching device to select any one ot' the several groups ot circuits, and means after an idle circuit in the group has been seized by the switching device for automatically and sequentially checking the various circuit conditions which arise during the normal operation o' the switch and the seized circuit.

2. A test set for testing a switch and the groups ot' trunks accessible thereto comprising, means tor setting the switch on the level assigned to any desired trunk group, means after the switch has seized an idle trunk in the selected level 'tor automatically and sequentially testing the various circuit conditions which arise during the normal operation oit the switch and the seized trunk, and

leans for causing the switch to pass on and seize the next idle trunk in the selected level,

asesinas after the tests on the trunk previously seized are completed.

3. A test set for testing a switch and the groups ot trunks accessible thereto comprising, means for setting the switch on the level assigned to the desired trunk group, means after the switch has seized an idle trunk in the selected level for automatically and sequentially testing the various circuit conditions which arise during the normal operation of the switch and th-e seized trunk, and means for preventing the tests from progressing when an improper circuitcondition is encountered.

4L. A test set for testing a switch and the groups ont' trunks accesible thereto comprising, means tor setting the switch on the level assigned to the desired trunk group, means after the switch has seized an idle' trunk in the selected level for automatically and sequentially testing'the various circuit conditions which will arise during the normal. operation ot' the switch and the seized trunk, means tor preventing the tests from progressing when an improper circuit condition is encountered, and means for causing the switch to step to the next trunk in the selected level.

5. A test set for testing a two-movement switch and the. groups ottrunks accessible thereto comprising means for initiating the primary movement of the switch which is thereby set on the level assigned to any desired. trunk group, and means, operative atter the secondary movement ot the switch is completed by the seizure of the first idle trunk in the group, for automatically and sequentially testing` the various circuit conditions which arise during the normal operation of the switch and the seized trunk.

A test set for testing ya two-movement switch and the groups ot trunks accessible thereto comprising means tor initiating the primary movement ot the switch which is thereby set on the levelassigned to any desired trunk group, means, operative after the secondary movement ot the switch is completed by the seizure ot the rst idle trunk in 'the group, for automatically and sequentially testing the various circuit conditions which arise during the normal operation ot the switch and the seized trunk, and means for causing the switch to reinitiat-e its secondary movement, whereby the next trunk in the level is seized after the series ot tests on the trunk previously seized is completed.

7. A test set tor testing a two-movement switch and the groups ot' trunks accessible thereto comprising means for initiating the primary movement oi the switch which is thereby set on the level assigned to any desired trunk group, and means, operative after the secondary movement of the switch lll) is completed by the seizure of the iirst `idle trunk, responsive to the various circuit conditions encountered during the operation of the switch and the seized trunk, whereby a series of tests progress automatically provided the circuit conditions encountered are normal.

S. A test set for testing a two-movement switch and the groups ot' trunks accessible thereto comprising means ior initiating the primary movement of the switch which is thereby set on the level assigned to any desired trunk group, and means, operative after the secondary movement of the switch is completed by the seizure of the iirst idle trunk, responsive to the various circuit conditions encountered during the operation of the switch and the seized trunk, whereby a series of tests progresses automatically provided the circuit conditions encountered are normal, but does not progress if an abnormal circuit condition is encountered.

9. A test set for testing a two-movement switch and the groups of trunks accessible thereto comprising means for initiating the primary movement of the switch which is thereby set on the level assigned to any desired trunk group, means operative after the secondary movement ot the switch is completed by the seizure of the iirst idle trunk, responsive to the various circuit con* ditions encountered during the operation of the switch and the seized trunk, whereby `a series of tests progresses automatically provided the circuit conditions encountered are normal, but does not progress if an abnorinal circuit condition is encountered, means for causing the switch to reinitiate its secondary movement whereby the next trunk in the level is seized, means for testing the trunk last seized to determine its busy or idle condition, and means ior preventing the series of tests from being repeated so long as the trunk last seized is busy.

10. A test set for testing a-two-movement switch and any group voi trunks accessible thereto comprising means for initiating the primary movement of the switch which is thereby set on the level assigned to the desired trunk group, means, operative after the secondary. movement of the switch is completed by the seizure or the 'iirst idle trunk, for initiating a series of tests on cach trunk in the group in succession until a busy trunk is encountered, and means'for resuming the test by initiating the series upon the busy trunk immediately it becomes idle.

11. A test set for testing ya two-movement switch and any group of trunks accessible thereto comprising means for initiating the primary movement of the `switch which is thereby set on the level assignedto the desired trunk group, means, operative after the secondary movement of the switch is completed by the seizure of the first idle trunk, tor initiating a series of tests on each trunk in the O'roup in succession until a busy or abnormal circuit condition is encountered on any trunk in the group, and means tor -reinitiating the secondary movement of the switch to pass by .the busy yor defective trunk circuit.

l2. A test set for testing a two-movement switch and any group of trunks accessible thereto comprising means for initiating the primary movement of the switch which is thereby set on the level assigned to the desired trunk group, means, operative after the secondary movement or' the switch is completed by the seizure oi' the first idle trunk, for initiating a series of tests on each trunk in the group in succession until the last trunk in the group has been tested, and means thereupon effective for allowing the two-movement switch to restore to normal.

13. A testing system, for testing a selector vswitch having botha primary and a secondary movement, and any group of trunks accessible thereto, comprising a test set, means in said test set including an impulse sender for initiating the primary movement of said switch which is thereby set on the level assigned to the desired trunk group, means in said test set operative after the secondary movement of the switchv is completed by the seizure of the first idle trunk for initiating a seriesvof tests on the remaining trunks in the group in succession until a busy trunk is encountered, and means included in ysaid test set for resuming the test by initiating the series upon the busy trunk immediately it becomes idle.

14. A testing system, for testing a selector switch having both a primary and a secondary move-ment, and any group of trunks accessible thereto, comprising a test set, means in said test set including an impulse sender for initiating the primary movement ot said switch which isthereby set on the level assigned to the desired trunk group, means in said test set operative after the secondary movement of i the switch is completed by the seizure of the first idle trunk for initiating a series of tests on the remaining trunks in the group in succession until a busy or abnormal circuit condition is encountered on any trunk in the group, and means in said test set for reinitiating the secondary movement of the switch to pass by the busy or defective trunk circuit. l

15. A testing system, for testing a selector switch having both a primary and a secondary movement, and any ,group of trunks accessible thereto, comprising a test set, means in said test set including an impulse sender :tor initiating the primary movement oi said switch which is thereby set on the level assigned to the desired after the secondary movement of the switch is completed by the seizure of the Viirst idle trunk for initiating@ series of tests on the remaining trunks in the group in succession until the last trunk in the group has been tested, and means thereupon eifective for allowing the selector switch to restore to normal. Y

In testimony whereof, We har-'e signed our 10 names to this specification this 15th day of August, 1924.

JAMES N. 'WALTERS CLAUDE EVING. 

